Seals between coaxial elements

Claim 2

In an apparatus having two elements which are coaxially disposed and relatively movable, a rolling diaphragm which is secured between adjacent walls of these elements and defines and separates a first space for containing gas and a second space for containing liquid for supporting the diaphragm, and control means operative with said apparatus for maintaining at least a substantially constant pressure differential across the diaphragm, the improvement in combination therewith comprising a second seal between said elements and located axially between said diaphragm and said first space which is thus divided into near and remote portions of the first space relative to said diaphragm, the second seal being operative on a diameter which is equal to the effective diameter of the diaphragm.

Claim 3

Apparatus according to claim 1 wherein one of said adjacent walls has a circumferential groove therein, and said second seal comprises a piston ring incorporated in said groove.

Claim 4

Apparatus according to claim 2 wherein said groove and piston ring therein define an annular space therebetween which is always in open communication with one of said near and remote portions of said first space.

Claim 5

Apparatus according to claim 1 wherein said seal is formed by a narrow gap.

Claim 6

In a hot gas engine having a compression piston axially movable within a cylindrical housing and defining a compression space above the piston, at least one rolling diaphragm seal between said piston and housing for defining and separating a substantially constant volume gas space above said seal and a liquid space below the seal, and a liquid supply, the gas space in communication with said compression space and the liquid space in communication with said liquid supply, and means for maintaining a substantially constant pressure differential across said diaphragm, the improvement in combination therewith comprising: a second sealing means formed as a piston ring disposed between and engaging said piston and housing, this ring being disposed axially between said diaphragm and compression space and operable as a one-way valve therebetween, this ring having an operative diameter equal to the effective diameter of the diaphragm seal for maintaining constant the volume above said diaphragm seal.

Claim 7

In a hot gas engine having a compression piston axially movable within a cylindrical housing and defining a compression space above the piston, at least one rolling diaphragm seal between said piston and housing for defining and separating a substantially constant volume gas space above said seal and a liquid space below the seal, and a liquid supply, the gas space in communication with said compression space and the liquid space in communication with said liquid supply, and means for maintaining a substantially constant pressure differential across said diaphragm, the improvement in combination therewith comprising: a second sealing means formed as a piston ring disposed between and engaging said piston and housing, this ring being disposed axially between said diaphragm and compression space and operable as a one-way valve therebetween, this ring having an operative diameter equal to the effective diameter of the diaphragm seal for maintaining constant the volume above said diaphragm seal.

Claim 8

Apparatus according to claim 5 wherein said ring permits gas flow only toward said compression space from said gas space above the diaphragm.

Claim 9

Apparatus according to claim 5 wherein said ring permits gas flow only toward said gas space above the diaphragm seal from said compression space.

Claim 10

Apparatus according to claim 5 wherein said piston includes a circumferential groove therein, said sealing ring is disposed within said groove with an annular space defined between the inside diameter surface of the ring and the adjacent surface of the groove.

Claim 11

Apparatus according to claim 8 wherein said piston includes internal duct means connecting said groove with a surface of the piston partially defining said compression space.

Claim 12

Apparatus according to claim 5 wherein said ring has at least one radial extending groove on a surface facing one of said compression and said gas spaces, said grooves permitting gas to flow past the ring in only one axial direction of the apparatus.

Claim 13

Apparatus according to claim 5 wherein the housing further comprises a buffer chamber intermediate said ring seal and said compression space, this chamber defined by the housing and a portion of the piston intermediate the ring seal and the end thereof defining the compression space, said buffer space having therein working medium at the same pressure as said working space, and the buffer space in open communication with said ring seal.